Method for transmitting and receiving signal based on LTE and NR in wireless communication system and apparatus therefor

ABSTRACT

The present invention relates to a method for an NR (New Radio Access Technology) user equipment to transmit and receive a signal in a wireless communication system and an apparatus therefor. The method comprises the steps of checking a PDCCH (Physical Downlink Control Channel) order and, if the PDCCH order is checked, initiating a random access procedure. In this case, if a first uplink carrier and a second uplink carrier are configured, the random access procedure is configured to transmit a random access preamble via a specific uplink carrier corresponding to an indicator associated with the PDCCH order among the first uplink carrier and the second uplink carrier.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/318,091, filed on Jan. 15, 2019, now allowed, which is a NationalStage application under 35 U.S.C. § 371 of International Application No.PCT/KR2018/008905, filed on Aug. 6, 2018, which claims the benefit ofU.S. Provisional Application No. 62/566,569, filed on Oct. 2, 2017, andU.S. Provisional Application No. 62/541,106, filed on Aug. 4, 2017. Thedisclosures of the prior applications are incorporated by reference intheir entirety.

TECHNICAL FIELD

The present invention relates to a wireless communication system, andmore particularly, to a method of transmitting and receiving a signalbased on LTE and NR in a wireless communication system and an apparatustherefor.

BACKGROUND

Wireless access systems have been widely deployed to provide varioustypes of communication services such as voice or data. In general, awireless access system is a multiple access system that supportscommunication of multiple users by sharing available system resources (abandwidth, transmission power, etc.) among them. For example, multipleaccess systems include a Code Division Multiple Access (CDMA) system, aFrequency Division Multiple Access (FDMA) system, a Time DivisionMultiple Access (TDMA) system, an Orthogonal Frequency Division MultipleAccess (OFDMA) system, a Single Carrier Frequency Division MultipleAccess (SC-FDMA) system, and the like.

As more communication devices require greater communication capacity,the necessity for mobile broadband communication which is enhancedcompared to a legacy radio access technology is emerging. And, massiveMTC (Machine Type Communication), which provides various services at anytime and any place by connecting a plurality of devices and objects, isalso one of main issues to be considered in next generationcommunication. Moreover, discussion on designing a communication systemconsidering a service/UE sensitive to reliability and latency is inprogress.

In particular, discussion on introducing a next generation wirelessaccess technology considering the enhanced mobile broadbandcommunication, the massive MTC, the URLLC (Ultra-Reliable and LowLatency Communication), and the like is in progress. In the presentinvention, for clarity, the next generation wireless access technologyis referred to as NR.

SUMMARY

Based on the aforementioned discussion, the present invention intends topropose a method of transmitting and receiving a signal based on LTE andNR in a wireless communication system and an apparatus therefor.

Technical tasks obtainable from the present invention are non-limitedthe above-mentioned technical task. And, other unmentioned technicaltasks can be clearly understood from the following description by thosehaving ordinary skill in the technical field to which the presentinvention pertains.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, accordingto one embodiment, a method of transmitting and receiving a signal,which is transmitted and received by an NR (New Radio Access Technology)terminal in a wireless communication system, includes the steps ofreceiving a PDCCH (Physical Downlink Control CHannel) order on adownlink carrier, and transmitting a random access preamble in responseto the PDCCH order. In this case, the random access preamble istransmitted on a first uplink carrier determined based on information onan uplink carrier included in the PDCCH order when a predeterminedcondition is satisfied, the predetermined condition comprises aplurality of uplink carrier including the first uplink carrier areconfigured for the downlink carrier, and a cell ID (Identification) ofthe downlink carrier and a cell ID of the plurality of uplink carrierare identical.

Moreover, the plurality of uplink carrier comprises a second uplinkcarrier, and the second uplink carrier is supplemental uplink carrierrelated with LTE (Long Term Evolution) band additionally assigned to theNR terminal.

Moreover, the random access preamble is transmitted via subcarrierspacing identical to a random access preamble transmission initiated bya higher layer when the first uplink carrier and the second uplinkcarrier are not configured.

Moreover, the method can further include the step of configuring atleast one of a time resource and a frequency resource to perform uplinktransmission. Or, the method can further include the step of receivingparameters to perform uplink transmission.

Moreover, the PDCCH order can be received using downlink (DL) controlinformation.

To further achieve these and other advantages and in accordance with thepurpose of the present invention, according to a different embodiment,an NR (New Radio Access Technology) terminal in a wireless communicationsystem includes an RF (radio frequency) unit, and a processor connectedwith the RF unit, the processor configured to control the RF unit toreceive a PDCCH (Physical Downlink Control Channel) order on a downlinkcarrier, and control the RF unit to transmit a random access preamble inresponse to the PDCCH order. In this case, the random access preamble istransmitted on a first uplink carrier determined based on information onan uplink carrier included in the PDCCH order when a predeterminedcondition is satisfied, the predetermined condition comprises aplurality of uplink carrier including the first uplink carrier areconfigured for the downlink carrier, and a cell ID (Identification) ofthe downlink carrier and a cell ID of the plurality of uplink carrierare identical.

According to embodiments of the present invention, it is able toefficiently transmit and receive a signal based on LTE and NR in awireless communication system.

Effects obtainable from the present invention may be non-limited by theabove mentioned effect. And, other unmentioned effects can be clearlyunderstood from the following description by those having ordinary skillin the technical field to which the present invention pertains.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is a schematic diagram of E-UMTS network structure as one exampleof a wireless communication system;

FIG. 2 is a diagram illustrating structures of a control plane and auser plane of a radio interface protocol between a user equipment andE-UTRAN based on the 3GPP radio access network standard;

FIG. 3 is a diagram illustrating physical channels used in a 3GPP LTEsystem and a general method for transmitting a signal using the physicalchannels;

FIG. 4 is a diagram illustrating a structure of a radio frame used in anLTE system;

FIG. 5 is a diagram for an example of a resource grid for a downlinkslot;

FIG. 6 is a diagram illustrating a structure of a downlink radio frameused in an LTE system;

FIG. 7 is a diagram illustrating a structure of an uplink subframe usedin an LTE system;

FIG. 8 is a diagram for explaining a self-contained slot structure in NRsystem;

FIGS. 9 and 10 are diagrams for explaining a connection scheme between aTXRU (Transceiver) and an antenna element;

FIG. 11 is a diagram for explaining hybrid beamforming;

FIG. 12 is a diagram for a base station and a UE applicable to oneembodiment of the present invention.

DETAILED DESCRIPTION

A 3rd generation partnership project long term evolution (3GPP LTE)(hereinafter, referred to as ‘LTE’) communication system which is anexample of a wireless communication system to which the presentinvention can be applied will be described in brief.

FIG. 1 is a diagram illustrating a network structure of an evolveduniversal mobile telecommunications system (E-UMTS) which is an exampleof a wireless communication system. The E-UMTS is an evolved version ofthe conventional UMTS, and its basic standardization is in progressunder the 3rd generation partnership project (3GPP). The E-UMTS may bereferred to as a long term evolution (LTE) system. Details of thetechnical specifications of the UMTS and E-UMTS may be understood withreference to Release 7 and Release 8 of “3rd Generation PartnershipProject; Technical Specification Group Radio Access Network”.

Referring to FIG. 1, the E-UMTS includes a user equipment (UE), basestations (eNode B; eNB), and an access gateway (AG) which is located atan end of a network (E-UTRAN) and connected to an external network. Thebase stations may simultaneously transmit multiple data streams for abroadcast service, a multicast service and/or a unicast service.

One or more cells exist for one base station. One cell is set to one ofbandwidths of 1.44, 3, 5, 10, 15 and 20 MHz to provide a downlink oruplink transport service to several user equipments (UEs). Differentcells may be set to provide different bandwidths. Also, one base stationcontrols data transmission and reception for a plurality of UEs. Thebase station transmits downlink (DL) scheduling information of downlinkdata to the corresponding UE to notify the corresponding UE of time andfrequency domains to which data will be transmitted and informationrelated to encoding, data size, and hybrid automatic repeat and request(HARQ). Also, the base station transmits uplink (UL) schedulinginformation of uplink data to the corresponding UE to notify thecorresponding UE of time and frequency domains that can be used by thecorresponding UE, and information related to encoding, data size, andHARQ. An interface for transmitting user traffic or control traffic maybe used between the base stations. A core network (CN) may include theAG and a network node or the like for user registration of the UE. TheAG manages mobility of the UE on a tracking area (TA) basis, wherein oneTA includes a plurality of cells.

Although the wireless communication technology developed based on WCDMAhas been evolved into LTE, request and expectation of users andproviders have continued to increase. Also, since another wirelessaccess technology is being continuously developed, new evolution of thewireless communication technology will be required for competitivenessin the future. In this respect, reduction of cost per bit, increase ofavailable service, use of adaptable frequency band, simple structure andopen type interface, proper power consumption of the UE, etc. arerequired.

The following technology may be used for various wireless accesstechnologies such as code division multiple access (CDMA), frequencydivision multiple access (FDMA), time division multiple access (TDMA),orthogonal frequency division multiple access (OFDMA), and singlecarrier frequency division multiple access (SC-FDMA). The CDMA may beimplemented by the radio technology such as universal terrestrial radioaccess (UTRA) or CDMA2000. The TDMA may be implemented by the radiotechnology such as global system for mobile communications (GSM)/generalpacket radio service (GPRS)/enhanced data rates for GSM evolution(EDGE). The OFDMA may be implemented by the radio technology such asIEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and evolved UTRA(E-UTRA). The UTRA is a part of a universal mobile telecommunicationssystem (UMTS). A 3rd generation partnership project long term evolution(3GPP LTE) is a part of an evolved UMTS (E-UMTS) that uses E-UTRA, andadopts OFDMA in a downlink (DL) and SC-FDMA in an uplink (UL).LTE-advanced (LTE-A) is an evolved version of the 3GPP LTE.

For clarification of the description, although the following embodimentswill be described based on the 3GPP LTE/LTE-A, it is to be understoodthat the technical spirits of the present invention are not limited tothe 3GPP LTE/LTE-A. Also, specific terminologies hereinafter used in theembodiments of the present invention are provided to assistunderstanding of the present invention, and various modifications may bemade in the specific terminologies within the range that they do notdepart from technical spirits of the present invention.

FIG. 2 is a diagram illustrating structures of a control plane and auser plane of a radio interface protocol between a user equipment (UE)and E-UTRAN based on the 3GPP radio access network standard. The controlplane means a passageway where control messages are transmitted, whereinthe control messages are used by the UE and the network to manage call.The user plane means a passageway where data generated in an applicationlayer, for example, voice data or Internet packet data are transmitted.

A physical layer as the first layer provides an information transferservice to an upper layer using a physical channel. The physical layeris connected to a medium access control (MAC) layer via a transportchannel, wherein the medium access control layer is located above thephysical layer. Data are transferred between the medium access controllayer and the physical layer via the transport channel. Data aretransferred between one physical layer of a transmitting side and theother physical layer of a receiving side via the physical channel. Thephysical channel uses time and frequency as radio resources. In moredetail, the physical channel is modulated in accordance with anorthogonal frequency division multiple access (OFDMA) scheme in a DL,and is modulated in accordance with a single carrier frequency divisionmultiple access (SC-FDMA) scheme in an uplink.

A medium access control (MAC) layer of the second layer provides aservice to a radio link control (RLC) layer above the MAC layer via alogical channel. The RLC layer of the second layer supports reliabledata transmission. The RLC layer may be implemented as a functionalblock inside the MAC layer. In order to effectively transmit data usingIP packets such as IPv4 or IPv6 within a radio interface having a narrowbandwidth, a packet data convergence protocol (PDCP) layer of the secondlayer performs header compression to reduce the size of unnecessarycontrol information.

A radio resource control (RRC) layer located on the lowest part of thethird layer is defined in the control plane only. The RRC layer isassociated with configuration, re-configuration and release of radiobearers (‘RBs’) to be in charge of controlling the logical, transportand physical channels. In this case, the RB means a service provided bythe second layer for the data transfer between the UE and the network.To this end, the RRC layers of the UE and the network exchange RRCmessage with each other. If the RRC layer of the UE is RRC connectedwith the RRC layer of the network, the UE is in an RRC connected mode.If not so, the UE is in an RRC idle mode. A non-access stratum (NAS)layer located above the RRC layer performs functions such as sessionmanagement and mobility management.

One cell constituting a base station eNB is set to one of bandwidths of1.4, 3, 5, 10, 15, and 20 MHz and provides a DL or UL transmissionservice to several UEs. At this time, different cells may be set toprovide different bandwidths.

As DL transport channels carrying data from the network to the UE, thereare provided a broadcast channel (BCH) carrying system information, apaging channel (PCH) carrying paging message, and a DL shared channel(SCH) carrying user traffic or control messages. Traffic or controlmessages of a DL multicast or broadcast service may be transmitted viathe DL SCH or an additional DL multicast channel (MCH). Meanwhile, as ULtransport channels carrying data from the UE to the network, there areprovided a random access channel (RACH) carrying an initial controlmessage and an UL shared channel (UL-SCH) carrying user traffic orcontrol message. As logical channels located above the transportchannels and mapped with the transport channels, there are provided abroadcast control channel (BCCH), a paging control channel (PCCH), acommon control channel (CCCH), a multicast control channel (MCCH), and amulticast traffic channel (MTCH).

FIG. 3 is a diagram illustrating physical channels used in a 3GPP LTEsystem and a general method for transmitting a signal using the physicalchannels.

The UE performs initial cell search such as synchronizing with the basestation when it newly enters a cell or the power is turned on at stepS301. To this end, the UE synchronizes with the base station byreceiving a primary synchronization channel (P-SCH) and a secondarysynchronization channel (S-SCH) from the base station, and acquiresinformation such as cell ID, etc. Afterwards, the UE may acquirebroadcast information within the cell by receiving a physical broadcastchannel (PBCH) from the base station. Meanwhile, the UE may identify aDL channel status by receiving a DL reference signal (DL RS) at theinitial cell search step.

The UE which has finished the initial cell search may acquire moredetailed system information by receiving a physical DL shared channel(PDSCH) in accordance with a physical DL control channel (PDCCH) andinformation carried in the PDCCH at step S302.

Afterwards, the UE may perform a random access procedure (RACH)according to steps S303 to S306 to complete access to the base station.To this end, the UE may transmit a preamble through a physical randomaccess channel (PRACH) (S303), and may receive a response message to thepreamble through the PDCCH and the PDSCH corresponding to the PDCCH(S304). In case of a contention based RACH, the UE may perform acontention resolution procedure such as transmission (S305) ofadditional physical random access channel and reception (S306) of thephysical DL control channel and the physical DL shared channelcorresponding to the physical DL control channel.

The UE which has performed the aforementioned steps may receive thephysical DL control channel (PDCCH)/physical DL shared channel (PDSCH)(S307) and transmit a physical UL shared channel (PUSCH) and a physicalUL control channel (PUCCH) (S308), as a general procedure oftransmitting UL/DL signals. Control information transmitted from the UEto the base station will be referred to as UL control information (UCI).The UCI includes hybrid automatic repeat and requestacknowledgement/negative-ack (HARQ ACK/NACK), scheduling request (SR),channel state information (CSI), etc. In this specification, the HARQACK/NACK will be referred to as HARQ-ACK or ACK/NACK (A/N). The HARQ-ACKincludes at least one of positive ACK (simply, referred to as ACK),negative ACK (NACK), DTX and NACK/DTX. The CSI includes channel qualityindicator (CQI), precoding matrix indicator (PMI), rank indication (RI),etc. Although the UCI is generally transmitted through the PUCCH, it maybe transmitted through the PUSCH if control information and traffic datashould be transmitted at the same time. Also, the UE maynon-periodically transmit the UCI through the PUSCH in accordance withrequest/command of the network.

FIG. 4 is a diagram illustrating a structure of a radio frame used in anLTE system.

Referring to FIG. 4, in a cellular OFDM radio packet communicationsystem, UL/DL data packet transmission is performed in a unit ofsubframe, wherein one subframe is defined by a given time interval thatincludes a plurality of OFDM symbols. The 3GPP LTE standard supports atype 1 radio frame structure applicable to frequency division duplex(FDD) and a type 2 radio frame structure applicable to time divisionduplex (TDD).

FIG. 4(a) is a diagram illustrating a structure of a type 1 radio frame.The DL radio frame includes 10 subframes, each of which includes twoslots in a time domain. A time required to transmit one subframe will bereferred to as a transmission time interval (TTI). For example, onesubframe may have a length of 1 ms, and one slot may have a length of0.5 ms. One slot includes a plurality of OFDM symbols in a time domainand a plurality of resource blocks (RB) in a frequency domain. Since the3GPP LTE system uses OFDM in a DL, OFDM symbols represent one symbolinterval. The OFDM symbol may be referred to as SC-FDMA symbol or symbolinterval. The resource block (RB) as a resource allocation unit mayinclude a plurality of continuous subcarriers in one slot.

The number of OFDM symbols included in one slot may be varied dependingon configuration of a cyclic prefix (CP). Examples of the CP include anextended CP and a normal CP. For example, if the OFDM symbols areconfigured by the normal CP, the number of OFDM symbols included in oneslot may be 7. If the OFDM symbols are configured by the extended CP,since the length of one OFDM symbol is increased, the number of OFDMsymbols included in one slot is smaller than that of OFDM symbols incase of the normal CP. For example, in case of the extended CP, thenumber of OFDM symbols included in one slot may be 6. If a channel stateis unstable like the case where the UE moves at high speed, the extendedCP may be used to reduce inter-symbol interference.

If the normal CP is used, since one slot includes seven OFDM symbols,one subframe includes 14 OFDM symbols. At this time, first maximum threeOFDM symbols of each subframe may be allocated to a physical DL controlchannel (PDCCH), and the other OFDM symbols may be allocated to aphysical DL shared channel (PDSCH).

FIG. 4(b) illustrates the structure of a type-2 radio frame. The type-2radio frame includes two half frames, each of which has 4 normalsubframes including 2 slots and a special subframe including a downlinkpilot time slot (DwPTS), a guard period (GP), and an uplink pilot timeslot (UpPTS).

In the special subframe, the DwPTS is used for initial cell search,synchronization, or channel estimation on a UE. The UpPTS is used forchannel estimation and acquisition of uplink transmissionsynchronization for a UE in an eNB. That is, the DwPTS is used fordownlink transmission, and the UpPTS is used for uplink transmission. Inparticular, the UpPTS is utilized for a PRACH preamble or SRStransmission. In addition, the GP is a period between uplink anddownlink, which is intended to eliminate uplink interference caused bymultipath delay of a downlink signal.

The current 3GPP standard document defines configuration of the specialsubframe as shown in Table 1 below. Table 1 shows DwPTS and UpPTS givenwhen T_(s)=1/(15000×2048), and the other region is configured as a GP.

TABLE 1 Normal cyclic prefix in downlink UpPTS Extended cyclic prefix indownlink Special Normal Extended UpPTS subframe cyclic prefix cyclicprefix Normal cyclic Extended cyclic configuration DwPTS in uplink inuplink DwPTS prefix in uplink prefix in uplink 0  6592 · T_(s) 2192 ·T_(s) 2560 · T_(s)  7680 · T_(s) 2192 · T_(s) 2560 · T_(s) 1 19760 ·T_(s) 20480 · T_(s) 2 21952 · T_(s) 23040 · T_(s) 3 24144 · T_(s) 25600· T_(s) 4 26336 · T_(s)  7680 · T_(s) 4384 · T_(s) 5120 · T_(s) 5  6592· T_(s) 4384 · T_(s) 5120 · T_(s) 20480 · T_(s) 6 19760 · T_(s) 23040 ·T_(s) 7 21952 · T_(s) 12800 · T_(s) 8 24144 · T_(s) — — — 9 13168 ·T_(s) — — —

In the TDD system, the structures of the type-2 radio subframe, namelyuplink/downlink subframe configurations (UL/DL configurations), aregiven as shown in Table 2 below.

TABLE 2 Downlink-to- Uplink- Uplink downlink Switch-point Subframenumber configuration periodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U U DS U U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms  DS U U U D D D D D 4 10 ms  D S U U D D D D D D 5 10 ms  D S U D D D D DD D 6 5 ms D S U U U D S U U D

In Table 2, D denotes a downlink subframe, U denotes an uplink subframe,and S denotes the special subframe. Table 2 also showsdownlink-to-uplink switch-point periodicity in uplink/downlink subframeconfiguration of each system.

The illustrated radio frame structures are merely illustrative, andvarious modifications may be made to the number of subframes included ina radio frame, the number of slots included in a subframe, or the numberof symbols included in a slot.

FIG. 5 is a diagram illustrating a resource grid of a downlink slot.

Referring to FIG. 5, the downlink slot includes a plurality of N_(symb)^(DL) OFDM symbols in a time domain and a plurality of N_(RB) ^(DL)resource blocks in a frequency domain. Since each resource blockincludes N_(sc) ^(RB) subcarriers, the downlink slot includes N_(RB)^(DL)×N_(sc) ^(RB) subcarriers in the frequency domain. Although FIG. 5illustrates that the downlink slot includes seven OFDM symbols and theresource block includes twelve subcarriers, it is to be understood thatthe downlink slot and the resource block are not limited to the exampleof FIG. 5. For example, the number of OFDM symbols included in thedownlink slot may be varied depending on the length of the CP.

Each element on the resource grid will be referred to as a resourceelement (RE). One resource element is indicated by one OFDM symbol indexand one subcarrier index. One RB includes N_(symb) ^(DL)×N_(sc) ^(RB)number of resource elements. The number N_(RB) ^(DL) of resource blocksincluded in the downlink slot depends on a downlink transmissionbandwidth configured in the cell.

FIG. 6 illustrates a structure of a downlink radio frame.

Referring to FIG. 6, up to 3 (or 4) OFDM symbols located at a head partof a first slot of a subframe correspond to a control region to which acontrol channel is assigned. And, the rest of OFDM symbols correspond toa data region to which PDSCH (physical downlink shared channel) isassigned. For example, DL control channels used in the LTE system mayinclude a PCFICH (physical control format indicator channel), a PDCCH(physical downlink control channel), a PHICH (physical hybrid ARQindicator channel) and the like. The PCFICH is transmitted on a firstOFDM symbol of a subframe and carries information on the number of OFDMsymbols in the subframe used for control channel transmission. The PHICHcarries an HARQ ACK/NACK (hybrid automatic repeat requestacknowledgment/negative-acknowledgment) signal in response to ULtransmission.

Control information transmitted on the PDCCH is called DCI (downlinkcontrol information). The DCI includes resource allocation informationand other control information for a user equipment or a user equipmentgroup. For instance, the DCI may include UL/DL scheduling information,UL transmission (Tx) power control command and the like.

The PDCCH carries transmission format and resource allocationinformation of a DL-SCH (downlink shared channel), transmission formatand resource allocation information of a UL-SCH (uplink shared channel),paging information on a PCH (paging channel), system information on aDL-SCH, resource allocation information of a higher-layer controlmessage such as a random access response transmitted on a PDSCH, a Txpower control command set for individual user equipments in a userequipment group, a Tx power control command, activation indicationinformation of a VoIP (voice over IP) and the like. A plurality ofPDCCHs may be transmitted in a control region. A user equipment canmonitor a plurality of PDCCHs. The PDCCH is transmitted on aggregationof one or more consecutive CCEs (control channel elements). In thiscase, the CCE is a logical assignment unit used in providing the PDCCHwith a coding rate based on a radio channel state. The CCE correspondsto a plurality of REGs (resource element groups). The PDCCH format andthe number of PDCCH bits are determined depending on the number of CCEs.A base station determines the PDCCH format in accordance with DCI to betransmitted to a user equipment and attaches CRC (cyclic redundancycheck) to control information. The CRC is masked with an identifier(e.g., RNTI (radio network temporary identifier)) in accordance with anowner or a purpose of use. For instance, if a PDCCH is provided for aspecific user equipment, CRC may be masked with an identifier (e.g.,C-RNTI (cell-RNTI)) of the corresponding user equipment. If a PDCCH isprovided for a paging message, CRC may be masked with a pagingidentifier (e.g., P-RNTI (paging-RNTI)). If a PDCCH is provided forsystem information (particularly, SIC (system information block)), CRCmay be masked with an SI-RNTI (system information-RNTI). In addition, ifa PDCCH is provided for a random access response, CRC may be masked withan RA-RNTI (random access-RNTI).

FIG. 7 is a diagram illustrating a structure of an uplink subframe usedin LTE.

Referring to FIG. 7, an uplink subframe includes a plurality of slots(e.g., 2 slots). A slot can include the different number of SC-FDMAsymbols depending on a CP length. An uplink subframe is divided into adata region and a control region in frequency domain. The data regionincludes PUSCH and is used for transmitting a data signal such as audioand the like. The control region includes PUCCH and is used fortransmitting uplink control information (UCI). PUCCH includes an RP pairpositioned at both ends of the data region in frequency axis and hops ata slot boundary.

PUCCH can be used for transmitting control information described in thefollowing.

SR (scheduling request): Information used for requesting uplink UL-SCHresource. OOK (on-off keying) scheme is used to transmit the SR.

HARQ ACK/NACK: Response signal for a DL data packet on PDSCH. Thisinformation indicates whether or not a DL data packet is successfullyreceived. ACK/NACK 1 bit is transmitted in response to a single DLcodeword. ACK/NACK 2 bits are transmitted in response to two DLcodewords.

CSI (channel state information): Feedback information on a DL channel.CSI includes a CQI (channel quality indicator) and MIMO (multiple inputmultiple output)-related feedback information includes an RI (rankindicator), a PMI (precoding matrix indicator), a PTI (precoding typeindicator) and the like. 20 bits per subframe are used.

An amount of control information (UCI) capable of being transmitted by auser equipment in a subframe is dependent on the number of SC-FDMAsavailable for transmitting control information. The SC-FDMAs availablefor transmitting the control information correspond to the remainingSC-FDMA symbols except SC-FDMA symbols used for transmitting a referencesignal in a subframe. In case of a subframe to which an SRS (soundingreference signal) is set, a last SC-FDMA symbol of a subframe is alsoexcluded. A reference signal is used for coherent detection of PUCCH.

In the following, a new radio access technology system is explained. Asmore communication devices require greater communication capacity, thenecessity for mobile broadband communication which is enhanced comparedto a legacy radio access technology is emerging. And, massive MTC(Machine Type Communication), which provides various services at anytime and any place by connecting a plurality of devices and objects, isalso required. Moreover, designing a communication system considering aservice/UE sensitive to reliability and latency has been proposed.

In particular, a new radio access technology system has been proposed asa new radio access technology considering the enhanced mobile broadbandcommunication, the massive MTC, the URLLC (Ultra-Reliable and LowLatency Communication), and the like. In the present invention, forclarity, the new radio access technology is referred to as New RAT or NR(New Radio).

An NR system to which the preset invention is applicable supportsvarious OFDM numerologies described in the following table. In thiscase, μ according to a carrier bandwidth part and cyclic prefixinformation can be signaled according to downlink (DL) and uplink (UL),respectively. For example, μ for a downlink carrier bandwidth part andcyclic prefix information can be signaled via higher layer signalingDL-BWP-mu and DL-MWP-cp. As a different example, μ for an uplink carrierbandwidth part and cyclic prefix information can be signaled via higherlayer signaling UL-BWP-mu and UL-MWP-cp.

TABLE 3 μ Δf = 2^(μ) · 15[kHz] Cyclic prefix 0 15 Normal 1 30 Normal 280 Normal, Extended 3 120 Normal 4 240 Normal

According to a frame structure of NR, DL and UL transmission areconfigured by a frame of a length of 10 ms. The frame can be configureby 10 subframes each of which has a length of 1 ms. In this case, thenumber of consecutive OFDM symbols in each subframe corresponds toN_(symb) ^(subframeμ)=N_(symb) ^(slot)N_(slot) ^(subframeμ).

Each frame can be configured by two half-frames each of which has thesame size. In this case, each of the half-frames can be configured bysubframes 0 to 4 and subframes 5 to 9, respectively.

For a subcarrier spacing μ, slots are numbered like n_(s) ^(μ)∈ {0, . .. , N_(slot) ^(subframe, μ)−1} in an ascending order within a subframeand can be numbered like n_(s,f) ^(μ)∈ {0, . . . , N_(slot)^(frame, μ)−1} in an ascending order within a frame. In this case, asshown in the table below, the number of consectuve OFDM symbols(N_(symb) ^(slot)) within a slot can be determined according to a cyclicprefic. A starting slot (n_(s) ^(μ)) in a subframe is aligned with astarting OFDM symbol in time domain in the same subframe. Table 4 in thefollowing illustrates the number of OFDM symbols for a normal cyclicprefic according to a slot, a frame, and a subframe and Table 5illustrates the number of OFDM symbols for an extended cyclic preficaccording to a slot, a frame, and a subframe.

TABLE 4 μ N_(symb) ^(slot) N_(slot) ^(frame, μ) N_(slot) ^(subframe, μ)0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16 5 14 320 32

TABLE 5 μ N_(symb) ^(slot) N_(slot) ^(frame, μ) N_(slot) ^(subframe, μ)2 12 40 4

In NR system to which the present invention is applicable, it may beable to apply a self-contained slot structure using the abovementionedslot structure.

FIG. 8 is a diagram illustrating a self-contained slot structureapplicable to the present invention.

In FIG. 8, a region of oblique lines (e.g., symbol index=0) correspondsto a downlink control region and a region of black color (e.g., symbolindex=13) corresponds to an uplink control region. The remaining region(e.g., symbol index=1˜12) can be used for transmitting either downlinkdata or uplink data.

A base station and a UE can sequentially perform DL transmission and ULtransmission in a single slot according to the structure above. The basestation and the UE can transmit and receive DL data in the slot and cantransmit and receive UL ACK/NACK in response to the DL data in the slot.Consequently, when a data transmission error occurs, the structurereduces time taken until data retransmission, thereby minimizing latencyof final data forwarding.

In order for a base station and a UE to switch from a transmission modeto a reception mode or switch from a reception mode to a transmissionmode in the self-contained slot structure, a time gap of a prescribedtime length is required. To this end, a partial OFDM symbol at thetiming of switching from DL to UL can be configured as a guard period(GP) in the self-contained slot structure.

In the foregoing description, although it is explained as aself-contained slot structure includes both a DL control region and a ULcontrol region, the control regions can be selectively included in theself-contained slot structure. In other word, as shown in FIG. 8, theself-contained slot structure according to the present invention caninclude both the DL control region and the UL control region. Or, theself-contained slot structure can include either the DL control regionor the UL control region only.

For example, slots may have various slot formats. In this case, OFDMsymbols of each slot can be classified into DL (D), flexible (X), and UL(U).

Hence, a UE may assume that DL transmission occurs in ‘D’ and ‘X’symbols only in a DL slot. Similarly, the UE may assume that ULtransmission occurs in ‘U’ and ‘X’ symbols only in a UL slot.

In the following, analog beamforming is explained.

Since a wavelength becomes short in the field of Millimeter Wave (mmW),a plurality of antenna elements can be installed in the same area. Inparticular, since a wavelength is 1 cm in a band of 30 GHz, if a 2Darray is installed in a panel of 5 by 5 cm with an interval of 0.5lambda (wavelength), it may be able to install the total 100 antennaelements. Therefore, in the field of mmW, it is able to increasecoverage or throughput by enhancing BF (beamforming) gain using aplurality of antenna elements.

In this case, each antenna port can include a transceiver unit (TXRU) tocontrol transmission power and phase according to an antenna element. Bydoing so, each antenna port can perform independent beamformingaccording to a frequency resource.

However, a problem occurs in that effectiveness is deteriorated in viewof cost when TXRU is provided for all of 100 antenna elements.Therefore, a scheme is considered, in which a plurality of antennaelements are mapped into one TXRU and a beam direction is controlled byan analog phase shifter. Since this analog beamforming scheme may makeonly one beam direction in a full band, a problem occurs in thatfrequency selective beamforming is not available.

As an intermediate type of digital BF and analog BF, a hybrid BF havingB TXRUs smaller than Q antenna elements may be considered. In this case,although there is a difference depending on a connection scheme of BTXRUs and Q antenna elements, the number of beam directions that enablesimultaneous transmission is limited to B or less.

FIGS. 9 and 10 are diagrams for explaining a connection scheme between aTXRU (Transceiver) and an antenna element. In this case, a TXRUvirtualization model illustrates a relationship between an output signalof a TXRU and an out signal of an antenna element.

FIG. 9 illustrates that TXRU is connected to a sub-array. In this case,the antenna elements are connected to only one TXRU.

Unlike FIG. 9, FIG. 10 illustrates that TXRU is connected to all antennaelements. In this case, the antenna elements are connected to all TXRUs.In this case, in order to make antenna elements to be connected to allTRXUs, as shown in FIG. 8, it is necessary to have an additional adder.

In FIGS. 9 and 10, W indicates a phase vector multiplied by an analogphase shifter. That is, a direction of analog beamforming is determinedby W. In this case, mapping between CSI-RS antenna ports and TXRUs maybe 1-to-1 or 1-to-many.

According to the configuration of FIG. 9, it may have a demerit in thatit is difficult to perform focusing of beamforming. On the other hand,it may have a merit in that it is able to configure the entire antennaswith low cost.

According to the configuration of FIG. 10, it may have a merit in thatit is easy to perform focusing of beamforming. On the contrary, sinceTRXUs are connected to all antenna elements, it may have a merit in thattotal cost increases.

In case of using a plurality of antennas in NR system to which thepresent invention is applicable, it may be able to apply a scheme ofhybrid beamforming corresponding to a combination of digital beamformingand analog beamforming. In this case, the analog beamforming (or RF(Radio Frequency) beamforming) corresponds to an operation of performingprecoding (or combining) at an RF end. In the hybrid beamforming, eachof a baseband end and an RF end performs precoding (or combining). Bydoing so, it may have a merit in that it is able to have performance asmuch as performance of digital beamforming while reducing the number ofRF chains and the number of D/A (Digital-to-Analog) (or A/D(Analog-to-Digital) converters.

For clarity, the hybrid beamforming structure can be represented by theN number of transceivers (TXRUs) and the M number of physical antennas.In this case, digital beamforming for the L number of data layers to betransmitted at a transmitting end can be represented by N*L (N by L)matrix. Subsequently, the N numbers of converted digital signals areconverted into analog signal via TXRUs and analog beamforming, which isrepresented by M*N (M by N) matrix, is applied to the converted signal.

FIG. 11 is a diagram briefly illustrating a hybrid beamforming structurein the aspect of TXRUs and physical antennas. In FIG. 11, the number ofdigital beams corresponds to L and the number of analog beamscorresponds to N.

In addition, NR system considers a method of more efficiently supportingbeamforming to a UE located at a specific region by designing analogbeamforming to be changed in a symbol unit by a base station. As shownin FIG. 11, when an antenna panel is defined by the N number of TXRUsand the M number of RF antennas, the NR system according to the presentinvention considers a method of introducing a plurality of antennapanels capable of applying independent hybrid beamforming.

As mentioned in the foregoing description, if a base station utilizes aplurality of analog beams, an analog beam advantageous for receiving asignal may vary according to a UE. In particular, in the NR system towhich the present invention is applicable, a beam sweeping operation isconsidered. In particular, a base station transmits a signal by applyinga different analog beam according to a symbol within a specific subframe(SF) to make all UEs have a reception opportunity.

In the present invention, when an NR UE and an NR base station areconnected to an LTE base station at the same time (dual connectivity) orwhen an NR UE corresponds to a UE to which an LTE band is additionallyassigned in UL (supplemental UL), a method of transmitting an uplinksignal of NR is explained. Although the present invention is describedcentering on a dual connected UE or a UE to which supplemental UL isassigned, the present invention can also be used for a differentscenario. For example, the present invention can be applied byconsidering a relationship between LTE and NR as a CA relationship inthe contents of the present invention.

Basically, a dual connected UE or a UE to which supplemental UL isassigned has a room for using two UL bands for a signal DL. In bothcases, since a legacy NR UL band and an LTE UL band exist together,there exists ambiguity in that it is difficult to determine whether a ULsignal is transmitted on the NR UL band or the LTE UL band. The presentinvention related to a method of transmitting a UL signal in thesituation above.

In the present invention, although such expressions as LTE downlink, LTEuplink, NR downlink, and NR uplink are used to explain the presentinvention, the expressions can be changed to downlink of a band X,uplink of a band Y, downlink of a band Z, and uplink of a band K,respectively, to apply the present invention to a different scenariorather than a dual connectivity situation. For example, the presentinvention can also be applied to a case that LTE band is used assupplemental UL. And, the present invention can be applied to allcombinations using a corresponding band combination such as NR CA, andthe like. The bands X, Y, Z, and K may correspond to bands including thepartly same part.

Embodiment 1

When NR UL signal is transmitted on LTE band, although the NR UL signalis scheduled in LTE scheduling request resource, the NR UL signal is nottransmitted in the LTE scheduling resource. This is because, since NRbase station is unable to know whether or not transmission is performedin the LTE scheduling request resource, although the NR UL signal isscheduled to an NR UE in the LTE scheduling request resource, the NRbase station can make the NR UE not to transmit the NR UL signal. Ingeneral, if LTE scheduling resource is configured, since it is a PUCCHregion, the LTE scheduling request resource can be applied to an NRPUCCH signal only.

The NR base station transmits configuration information on the LTEscheduling request resource to the NR UE in a manner of transceiving theconfiguration information on the LTE scheduling request resource betweenNR and LTE base station via X2 interface. In case of a dual connectedUE, the dual connected UE can transmit and receive configuration on LTEscheduling request resource configured by LTE via NR LTE upper layer orcan transmit the configuration to the NR base station.

The configuration on the LTE scheduling request resource corresponds toUE-specific information. However, it is able to configure theconfiguration to cell-specifically transmit and receive all informationon the LTE scheduling request resource in a dual connectivity or asupplemental UL situation.

In an LTE system, although LTE scheduling request resource configurationis allocated in a unit of a subframe, it may be able to apply the samerule to a case that the LTE scheduling request resource configuration isallocated in a unit of a slot or a symbol.

If LTE scheduling request configuration is allocated in a unit of a slotor a symbol, only a part of resources intending to transmit NR UL signalmay correspond to an LTE scheduling request resource. In this case, itmay be able to configure the NR UL signal to be transmitted byperforming rate matching on the part only. It may be able to inform a UEof information on whether to perform the rate matching via higher layersignaling (e.g., RRC signaling) or a control channel.

Although it is represented as an LTE scheduling request resourceposition, it may also apply the same rule to LTE ACK/NACK resource.

And, although it is represented as an LTE scheduling request resourceposition, positions of signals to be protected can be configured at atime. In particular, although NR UL signal is scheduled at thepositions, it may be able to define a rule that the NR UL signal is notto be transmitted at the positions.

If a UE fails to transmit NR UL signal due to LTE signal to beprotected, it may be able to inform the UE of information on whether theNR UL signal is transmitted again at certain timing or dropped via acontrol channel or higher layer signaling (e.g., RRC signaling).

If NR UL signal is allowed to be transmitted in LTE scheduling requestresource, power is checked only using on-off scheme not to detect asignal at the timing of performing scheduling request demodulation inLTE base station, and whether or not a modulated signal is transmittedis determined at the time of actually transmitting a scheduling request,although the NR UL signal and a scheduling request are transmittedtogether, it is able to detect the scheduling request. For example, whena scheduling request is transmitted, if a distance difference between amodulated signal and an estimated signal is equal to or less than aprescribed value, it can be determined as the scheduling request hasbeen transmitted.

Embodiment 2

According to embodiment 2 of the present invention, when NR UL signal isscheduled on LTE band, timing (or frequency position) at which PUSCH isscheduled or timing (or frequency position) at which ACK/NACK isscheduled can be indicated by a control channel or can besemi-statically defined via higher layer signaling (e.g., RRCsignaling). In this case, in may be able to separately indicate acarrier (or band) at which PUSCH or ACK/NACK is scheduled (via a controlchannel or RRC signaling).

For example, a base station can indicate one selected from amongcarriers described in the following.

A. LTE carrier

B. NR carrier

C. Both (i.e., LTE carrier and NR carrier)

In particular, the base station can indicate a carrier on which PUSCH orACK/NACK is transmitted among LTE carrier, NR carrier, or both the LTEcarrier and the NR carrier.

The base station can indicate both of the carriers (i.e., C) forreliability. In this case, it is able to repeatedly transmit a messageon the two carriers. Or, it may be able to transmit the message on thetwo carriers by dividing the message. Information on whether the messageis repeated or divided can be informed by a control channel or higherlayer (e.g., RRC signaling).

Embodiment 3

According to embodiment 3 of the present invention, when NR UL signal isscheduled on LTE band, NR and LTE UL may use a different numerology(i.e., a numerology having different subcarrier spacing). In this case,timing (or frequency position) at which PUSCH is scheduled or timing (orfrequency position) at which ACK/NACK is scheduled can be indicated by acontrol channel or can be semi-statically defined by higher layersignaling (e.g., RRC signaling). In this case, it may be able toindicate a unit of a TTI (transmission time interval) assumed on LTEcarrier (via a control channel or RRC signaling) separately or together.

And, it may be able to indicate transmission timing (via a controlchannel or RRC signaling) separately or together. For example, it may beable to indicate a symbol or a slot in which transmission is performedin a subframe.

Embodiment 4

As mentioned earlier in the embodiment 2 and the embodiment 3, when NRUL signal is scheduled on LTE band (or NR band), it may be able toconfigure a plurality of sets for UL timing, transmission numerology,and the like via RRC configuration and a control channel can indicate aset from among a plurality of the sets. In this case, parametersdescribed in the following can be included in a set.

A. Transmission numerology

B. A TTI unit for UL transmission timing (When transmission is performedat a certain TTI, it means a single TTI unit. If a plurality of TTIs aredefined in a manner of being bundled, for example, if three or foursymbols appear in turn, it may correspond to a TTI pattern.)

C. Transmission carrier

D. Reference signal structure (e.g., LTE UL DMRS or NR DMRS). In thiscase, values related to a sequence generation parameter of a referencesignal can also be included. This is because, when LTE signal and areference signal parameter occupy a resource together, it is necessaryto control the reference signal parameter to maintain orthogonalitybetween DMRSs. Or, a symbol position of a DMRS can also be included.This is because, when LTE signal and a DMRS occupy a resource together,it is necessary to orthogonally transmit the DMRS by placing the DMRS onthe same position between LTE and NR. In order to place the DMRS on thesame position between LTE and NR, it may shift a frame boundary of theNR. In this case, the shifting operation can be indicated via RRCconfiguration different from the parameters described in the embodiment4 or can be indicated by an indication different from the indication ofthe embodiment 4.

E. Precoding information. When a position is different between LTE andNR, although LTE and NR occupy the same resource, it may be able toconfigure precoding to make beams to be separated. To this end,precoding information of each UE can be exchanged between LTE and NR.The precoding may become precoding information less influencing on adifferent base station or precoding information of which a signalreceived by each base station is big.

Embodiment 5

If LTE and NR perform UL transmission at the same time in the sameresource, it may be able to indicate MU MIMO (multi-user multiple-inputand multiple-output) to be performed. Or, it may be able to configureMU-MIMO to be performed by PUCCH and PUSCH at a position of PUSCH onlywhen PUSCH/PUCCH simultaneous transmission is not performed.

For example, a DMRS is transmitted at the same position between LTE andNR and it may be able to configure sequences to be orthogonal to eachother. In this case, in order to place the DMRS on the same positionbetween LTE and NR, it may be able to shift a frame boundary of the NR.In this case, the shifting operation can be indicated via RRCconfiguration or an indication of a control channel.

When a position of NR is different from a position of LTE base stationdue to the application of precoding of each signal, it may be able toconfigure beams to be separated. To this end, precoding information of aUE can be exchanged between LTE and NR.

Or, it may be able to configure a UE to recognize MU-MIMO situation andinform each base station of the MU-MIMO situation when the UE performstransmission. Or, a base station can indicate a UE to performtransmission in MU-MIMO situation via RRC configuration or a controlchannel.

Embodiment 6

In embodiment 6, a piggyback rule is explained. In case of a dualconnected UE, both LTE PUSCH and NR UCI (Uplink Control Information) canbe scheduled on LTE band. In this case, it may be able to configure theNR UCI to use ACK/NACK resource position only while following apiggyback rule of LTE PYSCH/PUCCH. This is because, since PUSCH ispunctured in ACK/NACK resource only, although LTE base station does notknow whether or not piggyback is performed, the LTE base station canperform demodulation on the PUSCH.

If piggyback is performed on a resource rather than an ACK/NACK resourceposition, it may be able to perform puncturing on PUSCH at a position ofthe resource. When rate matching is performed on PUSCH, if LTE basestation does not know whether or not piggyback is performed, the LTEbase station fails to perform LTE PUSCH demodulation.

Or, a UE may inform an NR base station of information on whether or notpiggyback is performed. The NR base station demodulates NT UL signalaccording to a piggyback rule. In this case, in order to indicateinformation on whether or not piggyback is performed, it may be able totransmit an additional sequence orthogonal to a DMRS in a ULtransmission subframe. And, in order to indicate information on whetheror not piggyback is performed, a UE can inform NR base station of theinformation via signaling between the timing at which scheduling is madeand the timing at which an UL signal is transmitted. A resource for thesignaling can be indicated to the UE via a DL control channel or RRCsignaling.

Or, it may be able to configure the UE to inform the NR base station ofthe information on whether or not piggyback is performed withoutfollowing the LTE piggyback rule. And, the NR and the LTE base statincan demodulate a UL signal according to the piggyback rule sharedbetween the NR and the LTE base station.

Or, if the piggyback is performed, the NR base station can performchannel estimation for demodulation via a DMRS transmitted for the LTE.Or, it may separately transmit NR DMRS at LTE PUSCH position and LTEPUSCH is punctured at the position.

Or, it may use LTE PUSCH and NR PUCCH in a symbol unit by performing TDM(Time Division Multiplexing) on the LTE PUSCH and the NR PUCCH. In thiscase, the LTE PUSCH is punctured in time at which the NR PUCCH istransmitted and the NR PUCCH can be transmitted in a PUCCH region.

Or, LTE PUSCH is transmitted and NR PUCCH can be dropped. The timing atwhich the dropped NR PUCCH is transmitted again can be indicated via acontrol channel or higher layer signaling (e.g., RRC signaling).

Or, it may be able to transmit LTE PUSCH and NR PUCCH in a form ofMU-MIMO by applying precoding to the LTE PUSCH and the NR PUCCH. In thiscase, it may be able to transmit the NR PUCCH and the LTE PUSCH in aform of superposition by sharing all or a part of resources of the NRPUCCH and the LTE PUSCH. To this end, precoding information of a UE canbe exchanged between the LTE and the NR. Or, it may be able to configuresequences to be orthogonal to each other by changing a parameter while aDMRS position is placed on the same position between the LTE and the NRtransmission. In order to place the DMRS position on the same position,it may be able to shift a frame boundary of the NR. In this case, theshifting operation can be indicated via RRC configuration or anindication of a control channel.

Unlike the embodiment 6, both NR PUSCH and LTE UCI can be scheduled onLTE band. In this case, although it is able to basically apply a schemesimilar to the embodiment 6, since it is difficult for the LTE to knowinformation on whether or not piggyback is performed, the LTE UCI istransmitted and the NR PUSCH can be dropped. The timing at which thedropped NR PUSCH is transmitted again can be indicated via a controlchannel or higher layer signaling (e.g., RRC signaling).

Embodiment 7

A PDCCH order is explained in the embodiment 7. In general, if syncinformation is not matched, a base station transmits a PDCCH order to aUE to indicate the UE to transmit RACH (random access channel). In thiscase, having received the PDCCH order, since the UE follows a contentionfree random access procedure, the UE transmits a random access preambleto the base station. The base station transmits a random access responseto the UE and provides information on TA (Timing Advance) to the UE. Inorder to transmit ACK/NACK in response to the information on the TA, thebase station schedules PUSCH to the UE.

The operation above has no significant problem in a current LTEoperation. However, in case of NR UE to which LTE band is assigned bysupplemental UL, ambiguity occurs on the NR UE. In particular, it isdifficult for the NR UE to determine whether transmission is to beperformed in NR UL or LTE UL.

According to the present invention, it may be able to perform a PDCCHorder-related RACH operation in consideration of operations 7-A to 7-Ddescribed in the following.

7-A: When a base station transmits a PDCCH order to a UE, the basestation can indicate a carrier as well. The carrier information can beindicated together when a time-frequency resource in which a randomaccess preamble is transmitted is indicated. The carrier information canindicate a carrier among two carriers. Or, the carrier information canindicate both of the two carriers such that signals can be transmittedon both of the two carriers.

7-B: When the UE transmits a random access preamble, the UE can transmitthe random access preamble on the carrier indicated by the operation of7-A.

7-C: The base statin transmits a random access response to the UE inresponse to the random access preamble. In this case, the base stationadditionally transmits carrier information to the UE to designate acarrier for performing 7-D operation to make the UE transmit ACK/NACK inresponse to the 7-C operation. The carrier information can indicate acarrier among two carriers. Or, the carrier information can indicateboth of the two carriers such that signals can be transmitted on both ofthe two carriers.

7-D: If a carrier on which ACK/NACK is transmitted in response to the7-C operation is indicated according to the 7-C operation, the UEtransmits ACK/NACK on the carrier. Otherwise, the UE transmits ACK/NACKon a carrier used in the 7-B operation.

In the embodiment 7, although it is able to indicate carrier informationin the 7-A operation and the 7-C operation, it may be able to inform theUE of a carrier to be used for transmission in the 7-B operation and the7-D operation via higher layer signaling (e.g., RRC signaling). In thiscase, it may be able to inform the UE of a carrier for the 7-B operationand a carrier for the 7-D operation, respectively. Or, it may be able toinform the UE of a single carrier only under the assumption thattransmission is performed on the same carrier. Or, it may be able toindicate the UE to perform the 7-B operation and the 7-D operation onthe two carriers. When the 7-B operation or the 7-D operation isperformed on the two carriers, a signal can be repeatedly transmitted onthe two carriers for each of the operations. Or, a signal can betransmitted on the two carriers by dividing the signal. Information onwhether a signal is repeated or divided can be informed by a controlchannel or higher layer (e.g., RRC signaling).

According to the embodiment 7, the operations 7-A to 7-D are describedby specific terms used in LTE such as a PDCCH order, a random accesspreamble, a random access response, and the like. However, an operationof the same form can be differently expressed in NR and the presentinvention can also be applied to the operation. For example, the 7-Aoperation may correspond to an operation for transmitting RACH to checksynchronization when synchronization is not matched. The 7-B operationmay correspond to an operation of transmitting RACH according to theoperation 7-A. The 7-C operation may correspond to an operation ofindicating TA via the RACH of the 7-B operation. The 7-D operation maycorrespond to an operation of transmitting ACK/NACK response in responseto the 7-C operation.

Moreover, since there are one DL and two ULs in supplemental ULenvironment, it is necessary to determine a UL on which PUSCH and PUCCHare to be transmitted. As a simple method, PUSCH and PUCCH aretransmitted on a single carrier and the carrier can be determinedaccording to a DL RSRP threshold. Or, a base station can determine thecarrier via RRC configuration or MAC CE.

In the case where the PRACH transmission is determined according to thedownlink RSRP threshold or is designated by RRC signaling, carrier onwhich PUCCH and PUSCH are transmitted can also be used for transmittingPRACH.

Embodiment 8

If a carrier to be transmitted is designated via RRC signaling or MAC CE(MAC Control Element), a time section ranging from the timing at whichthe RRC signaling or the MAC CE is forwarded to a UE to the timing atwhich the RRC signaling or the MAC CE is checked is ambiguous in theaspect of a base station. Hence, the embodiment 8 proposes operations8-A to 8-C.

If a carrier on which PUCCH and PUSCH (or PRACH as well) are to betransmitted is indicated to a UE via RRC configuration or MAC CE, duringprescribed time after the RRC configuration or the MAC CE is received,

8-A: it may use a currently used carrier and then move to the indicatedcarrier.

8-B: for example, if a carrier on which PUCCH and PUSCH are to betransmitted is independently configured, it may use a currently usedPRACH carrier and then move to the indicated carrier.

8-C: it may use a predetermined carrier and then move to the indicatedcarrier. The predetermined carrier can be promised in advance or can beindicated via RRC configuration or MAC CE.

In particular, in case of using a single carrier, it is preferable thata physical cell ID of SUL (supplemental UL) is same as a physical cellID of DL. This is because, since two ULs are used while time switchingis performed, the two ULs can be managed in a manner of being regardedas single UL.

In this case, SUL and DL/UL may have different subcarrier spacing.Hence, a change can be made on scheduled PUSCH timing and HARQ ACK/NACKtiming. Basically, when two ULs are used through time switching,scheduling PUSCH timing and HARQ ACK/NACK timing are indicated on thebasis of DL/UL and the scheduling PUSCH timing and the HARQ ACK/NACKtiming are used in a manner of being reinterpreted without additionalindication for SUL. This is because, if it is assumed that time takenbetween PDCCH and PUSCH or time taken between PDSCH and PUCCH has nodifference with SUL in UL, it is preferable to use the same schedulingPUSCH timing or the HARQ ACK/NACK timing. To this end, since UL and SULhave a different slot length, scheduled PUSCH or HARQ ACK/NACK istransmitted in a slot of SUL which appears later as much as anindication of the scheduling PUSCH timing and an indication of the HARQACK/NACK timing on the basis of a slot length of DL.

Embodiment 9

If a carrier on which PUSCH/PUCCH is to be transmitted is determined viaRRC or MAC CE in SUL, ambiguity may occur on a periodic UL signal (e.g.,periodic CSI). When a periodic signal is transmitted, if a carrier ischanged between transmission periods and UL and SUL have a differentnumerology, it is difficult for a UE to determine a resource and aformat to be used for transmission after the carrier is changed. Hence,embodiment 9 of the present invention may consider operations 9-A to 9-Cdescribed in the following.

9-A: In SUL, if PUSCH for transmitting a periodic UL signal or a carrierfor transmitting PUCCH is changed in the middle of transmitting theperiodic UL signal, since the carrier is changed, periodic UL signaltransmission used to be transmitted on a previous carrier is notperformed on a new carrier. If a carrier is returned to the carrier onwhich the periodic UL signal used to be transmitted, the periodic ULsignal transmission is resumed.

9-B: In SUL, if PUSCH for transmitting a periodic UL signal or a carrierfor transmitting PUCCH is changed in the middle of transmitting theperiodic UL signal, although the carrier is changed, since the most ofperiodic UL signals are not channel-dependent transmission (except SRS)of the carrier, transmission of the periodic UL signal is maintainedirrespective of the change of the carrier. In this case, it is necessaryfor a base station to set a configuration (resource configuration,transmission format configuration) for the periodic UL signal to a UEfor two carriers including UL and SUL. The UE performs periodic ULsignal transmission according to the configuration in accordance withthe transmission carrier.

9-C. 9-A: In SUL, if PUSCH for transmitting a periodic UL signal or acarrier for transmitting PUCCH is changed in the middle of transmittingthe periodic UL signal, although the carrier is changed, the periodic ULsignal used to be transmitted on a previous carrier can be continuouslytransmitted on the previous carrier.

Moreover, SUL may be able to share a band currently used in a differentRAT or a band. Meanwhile, a cell ID is used for performing datascrambling and generating a reference signal sequence to performinterference randomization. Hence, it is preferable for SUL to use acurrently shared band or a cell ID of RAT in the aspect of a network.

FIG. 12 is a diagram for a base station and a UE applicable to oneembodiment of the present invention.

If a relay is included in a wireless communication system, communicationis performed between a base station and the relay in backhaul link andcommunication is performed between the relay and a user equipment inaccess link. Hence, the base station and the user equipment shown in thedrawing can be replaced with the relay in accordance with a situation.

Referring to FIG. 12, a wireless communication system includes a basestation (BS) 110 and a user equipment (UE) 120. The BS 110 includes aprocessor 112, a memory 114 and a radio frequency (RF) unit 116. Theprocessor 112 can be configured to implement the proposed functions,processes and/or methods. The memory 114 is connected with the processor112 and then stores various kinds of information associated with anoperation of the processor 112. The RF unit 116 is connected with theprocessor 112 and transmits and/or receives a radio signal. The userequipment 120 includes a processor 122, a memory 124 and a radiofrequency (RF) unit 126. The processor 122 can be configured toimplement the proposed functions, processes and/or methods. The memory124 is connected with the processor 122 and then stores various kinds ofinformation associated with an operation of the processor 122. The RFunit 126 is connected with the processor 122 and transmits and/orreceives a radio signal. The base station 110 and/or the user equipment120 may have a single antenna or multiple antennas.

The above-described embodiments correspond to combinations of elementsand features of the present invention in prescribed forms. And, therespective elements or features may be considered as selective unlessthey are explicitly mentioned. Each of the elements or features can beimplemented in a form failing to be combined with other elements orfeatures. Moreover, it is able to implement an embodiment of the presentinvention by combining elements and/or features together in part. Asequence of operations explained for each embodiment of the presentinvention can be modified. Some configurations or features of oneembodiment can be included in another embodiment or can be substitutedfor corresponding configurations or features of another embodiment. And,it is apparently understandable that an embodiment is configured bycombining claims failing to have relation of explicit citation in theappended claims together or can be included as new claims by amendmentafter filing an application.

In this disclosure, a specific operation explained as performed by abase station may be performed by an upper node of the base station insome cases. In particular, in a network constructed with a plurality ofnetwork nodes including a base station, it is apparent that variousoperations performed for communication with a user equipment can beperformed by a base station or other networks except the base station.‘Base station (BS)’ may be substituted with such a terminology as afixed station, a Node B, an eNode B (eNB), an access point (AP) and thelike.

Embodiments of the present invention can be implemented using variousmeans. For instance, embodiments of the present invention can beimplemented using hardware, firmware, software and/or any combinationsthereof. In the implementation by hardware, a method according to eachembodiment of the present invention can be implemented by at least oneselected from the group consisting of ASICs (application specificintegrated circuits), DSPs (digital signal processors), DSPDs (digitalsignal processing devices), PLDs (programmable logic devices), FPGAs(field programmable gate arrays), processor, controller,microcontroller, microprocessor and the like.

In case of the implementation by firmware or software, a methodaccording to each embodiment of the present invention can be implementedby modules, procedures, and/or functions for performing theabove-explained functions or operations. Software code is stored in amemory unit and is then drivable by a processor.

The memory unit is provided within or outside the processor to exchangedata with the processor through the various means known in public.

While the present invention has been described and illustrated hereinwith reference to the preferred embodiments thereof, it will be apparentto those skilled in the art that various modifications and variationscan be made therein without departing from the spirit and scope of theinvention. Thus, it is intended that the present invention covers themodifications and variations of this invention that come within thescope of the appended claims and their equivalents.

A method of transmitting and receiving a signal based on LTE and NR in awireless communication system and an apparatus therefor can be appliedto various wireless communication systems.

What is claimed is:
 1. A method for performing a random access procedureby a user equipment (UE) in a wireless communication system, the methodcomprising: receiving downlink control information (DCI) through aphysical downlink control channel (PDCCH) on a first downlink (DL)carrier of a serving cell configured for the UE; and transmitting arandom access preamble based on the DCI being a PDCCH order whichinitiates the random access procedure, wherein the serving cellconfigured for the UE comprises the first DL carrier, a first uplink(UL) carrier and a second UL carrier, wherein a same physical cellidentifier is configured for the first DL carrier, the first UL carrierand the second UL carrier, wherein the second UL carrier is asupplementary uplink (SUL) carrier, and wherein an UL carrier fortransmitting the random access preamble is determined between the firstUL carrier and the SUL carrier based on UL carrier indicationinformation included in the DCI.
 2. The method of claim 1, wherein therandom access preamble is based on subcarrier spacing identical tosubcarrier spacing of a random access preamble transmission initiated bya radio access control (RRC) layer before the first UL carrier and thesecond UL carrier are configured for the UE.
 3. The method of claim 1,wherein the first DL carrier and the first UL carrier are configured ina new radio technology (NR) band.
 4. The method of claim 1, wherein theSUL carrier is configured in a long term evolution (LTE) band.
 5. A userequipment (UE) configured to perform a random access procedure in awireless communication system, the UE comprising: a transceiver; and atleast one processor coupled with the transceiver, wherein the at leastone processor is configured to: receive downlink control information(DCI) through a physical downlink control channel (PDCCH) on a firstdownlink (DL) carrier of a serving cell configured for the UE; andtransmit a random access preamble based on the DCI being a PDCCH orderwhich initiates the random access procedure, wherein the serving cellconfigured for the UE comprises the first DL carrier, a first uplink(UL) carrier and a second UL carrier, wherein a same physical cellidentifier is configured for the first DL carrier, the first UL carrierand the second UL carrier, wherein the second UL carrier is asupplementary uplink (SUL) carrier, and wherein an UL carrier fortransmitting the random access preamble is determined between the firstUL carrier and the SUL carrier based on UL carrier indicationinformation included in the DCI.
 6. An apparatus configured to control auser equipment (UE) to perform a random access procedure in a wirelesscommunication system, the apparatus comprising: at least one processor;and at least one memory operably connectable to the at least oneprocessor and storing instructions that, based on executed, cause the atleast one processor perform operations comprising: receiving downlinkcontrol information (DCI) through a physical downlink control channel(PDCCH) on a first downlink (DL) carrier of a serving cell configuredfor the UE; and transmitting a random access preamble based on the DCIbeing a PDCCH order which initiates the random access procedure, whereinthe serving cell configured for the UE comprises the first DL carrier, afirst uplink (UL) carrier and a second UL carrier, wherein a samephysical cell identifier is configured for the first DL carrier, thefirst UL carrier and the second UL carrier, wherein the second ULcarrier is a supplementary uplink (SUL) carrier, and wherein an ULcarrier for transmitting the random access preamble is determinedbetween the first UL carrier and the SUL carrier based on UL carrierindication information included in the DCI.